The man with the chainsaw heads straight for me. His face is contorted in a mask of pure hate and the power tool is roaring above his head. Around me, girls are swerving behind quivering boyfriends who are inching backwards into the billowing fog that suffocates the street. For a moment, I am terrified, frozen to the spot imagining how it will feel to have a saw grind through my flesh, bone and muscle. I'm guessing being murdered to pieces will be painful.

Then I remember I am in a theme park. The mask of hate is actually a mask of rubber, his chainsaw will have been denatured and none of this - not even the fog - is real. Best of all, I am in America so if this demented DIY expert as much as disturbs a hair on my head, I will see him and Universal Studios in court.

Yet even this doesn't stop the whole experience being quite terrifying. Besides, as everyone knows from watching scary movies, the Big Bad can appear out of nowhere (the gloomy basement, the summer camp woodshed) and turn you into his supper. It is perhaps for this reason my heart is pumping, my palms are sweating and my eyes are wide, even after Chainsaw Man has turned his attentions towards some other nervous soul who, at this very moment, is slurping a jumbo cup of cola as if it were bravery juice. After whooping like a girl, I begin to laugh nervously in that well-of-course-I-wasn't-really-scared kind of way.

This is Universal Studios' Islands of Adventure theme park. Only, for most of these October evenings, it has been transformed into Islands of Fear. The story - for there is a story behind everything here - is that the islands have been taken over by the forces of darkness (or perhaps the Forces of Darkness) led by the monstrous caretaker (or, more likely, the Caretaker). The Caretaker cuts out his victims' hearts and has very bad teeth. It is unclear which is the more heinous crime in America.

The Caretaker has enabled villains to take over Marvel Super Hero Island and has unleashed half-man, half-dinosaur mutants in Jurassic Park. The Lost Continent has become the Island of Lost Souls, over which the evil Nightmare has dominion, and Toon Lagoon has become a freakish caricature of its former self. See what I mean about the stories?

And here I am - someone who takes no pleasure in being scared - standing in line for a horror maze called Screamhouse. Themed around the smalltown mortuary of the Caine family, it is one of four labyrinths devised by Universal's "scream team" of designers and infested by a variety of monsters, mutants and maniacs - which is to say, out-of-work actors in horror-film costumes who take their roles very seriously.

Inside the maze, it goes from gloomy to pitch black and back again. Feeling your way about winding corridors, every corner conceals a ghost or ghoul or else limitless darkness. I'm not sure which is worse. Curtains, wisps of material and body bags hang from the ceiling and you have to push your way through them, unsure of what lurks beyond. Smoke is pumped in, a strobe light begins pulsing and you can see nothing. You are propelled forward - the queue is pushing at your back - but every step is taken with reluctance. You cling to the person in front of you, you scream in spite of yourself and you are desperate to get to the end. Eventually, you exit. There is fresh air. You can see the sky. Everyone around you is laughing that nervous laughter. And then you have the chainsaw people to deal with again.

It's not as if Orlando isn't scary enough, what with the obesity epidemic, the inane smiling and the conversations that go nowhere. And then there's the metal detectors all guests have to pass through to get into the Islands of Fear.

Perhaps scary is too strong a word, but Orlando is probably the only destination on the planet you go to not to actually go there but to seep up whatever "theme" a particular area, hotel or park has been doused in. At Universal, for example, you can stay in the Royal Pacific Resort (South Sea islands theme), the Portofino Bay Hotel (Italian Riveria theme) or the Hard Rock Hotel, the theme of which you can probably work out for yourself. Nothing feels real, everything is simulacra. Perhaps the word is "odd".

Back on the Islands of Fear, it's clear you're not in Disney any more, Toto. With the opening of its hotels earlier this year, Universal has become a proper resort and a real rival of Disney for tourist dollars. For a decade, it has survived on the spillover from the mighty Mouse 15 miles down the interstate but after five years of building frenzy, it has come of age. Universal's lot may only be a tenth of the size of the Disney compound - which covers an area larger than the island of Manhattan - and it might only have 48 attractions compared with Disney's 115, but there is a certain something about Universal that Disney doesn't have - an edge. It may only be a smooth, sanitised Orlando edge, but it's an edge nonetheless. Were theHalloween Horror Nights shenanigans occurring down the Magic Kingdom, Walt would surely be spinning in his cryogenic freezer.

Getting there: Virgin Holidays (0871 2221900, Virgin Holidays) offers seven-night packages from £979 per adult, under 10s from £379, teens from £459, including direct flights, accommodation, car hire or transfers and the Universal Pass giving unlimited access to the two theme parks and City Walk, its entertainment district (Universal Orlando).

Terror of the Towers

Alton Towers, in Staffordshire, has been hosting Halloween events for some time, but they have always been aimed at younger children, the under-12s mainly. This year, the Cadbury's Spooktacular is running in three areas of the park. In Cred Street, a storytelling witch relates tales of ghosts, monsters and ghouls. In Adventureland, there is a haunted hall of mirrors. On Towers Street, there is a Trick or Treat zone. Needless to say, funsize chocolate bars are everywhere. While little else is overtly themed, spooky accoutrements have inevitably spilled over into the rest of the park. A cobweb here, a giant spongey spider there.

It is in the ruins that Tussauds, owners of Alton Towers, have placed their first attempt to cater for the over-12s audience at Halloween. The Terror of the Towers maze has been designed by Lynton V Harris, who has built quite a reputation in America as the brains behind some of the nation's most famous horror attractions, including the notorious Madison Scare Garden. This, and the companion mazes at Thorpe Park, are his first live horror attractions in Europe.

You enter the towers' ruins and are greeted by a hag who arranges you into groups of six. You are then ushered into the building proper and begin what could either be a shuffle or a sprint - depending on how you and your group react to ghosts and ghouls jumping out the dark and at you - through a specially constructed corridor with plenty of dark corners. With smoke, strobe lights and a suitably spooky soundtrack, it is quite scary and certainly has the potential to be terrifying. Currently, however - and this is only its first year - it is not so much spine-chilling as off-putting, though the 13-year-old girl in front of me in the queue might disagree with that. If you are of a nervous disposition, it perhaps isn't for you.

The Terror of the Towers maze doesn't have the fear factor of Universal's Florida version at Halloween Horror Nights. Quite simply, it doesn't have the huge production values or the hardened audience that the Orlando theme park attracts. Nor does Staffordshire have an abundance of out-of-work actors willing to don rubber masks, wield plastic machetes and screech at the tops of their voices. What it does have, though, is a certain earthy eeriness.

Where to book: The Terror of the Towers Maze runs until Nov 3. Prices start from £23.50 for adults and £19.50 for children including all Halloween activities. See altontowers.com or call 08705 204060 for opening times. The Freezer and Freakshow at Thorpe Park (Thorpe Park, 0870 4444466) on October 31 and Nov 1-3 costs from £17 for adults and £14.50 for children.